Once you refrigerate it, all the yeast will drop to the bottom. It makes it easy to move the cider to a new container. Most of the bubbling will have stopped. My recipe is semi-sweet even after sitting in the fridge for a year. If you let them ferment longer than 3 weeks, then it will get dryer as the yeast eat the sugar. Taste it in 3 weeks or earlier, if it tastes good, you're done. If the sweetness is good but it tastes a little bitter or has an off flavor, that's when you need to let it age in the fridge. Fill up a 2 liter bottle and stick it in the back of the fridge and forget about it.

Yes, when it's done, keep it refrigerated. I refrigerate the cider and rack to a new container when the yeast drops out. There's still going to be some yeast in there and they will be a little active in the fridge. I've noticed that after I let the cider age 6 months to a year, the yeast that's left over actually carbonates it nicely. I've never bottled it in glass, if you do, you want some yeast in there for carbonation. If you force carbonate, you don't need the yeast but they won't hurt anything. It'll be an extra step to get rid of them.Good Luck.